linux/fs/ubifs/misc.h
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   1/*
   2 * This file is part of UBIFS.
   3 *
   4 * Copyright (C) 2006-2008 Nokia Corporation
   5 *
   6 * This program is free software; you can redistribute it and/or modify it
   7 * under the terms of the GNU General Public License version 2 as published by
   8 * the Free Software Foundation.
   9 *
  10 * This program is distributed in the hope that it will be useful, but WITHOUT
  11 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  12 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
  13 * more details.
  14 *
  15 * You should have received a copy of the GNU General Public License along with
  16 * this program; if not, write to the Free Software Foundation, Inc., 51
  17 * Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
  18 *
  19 * Authors: Artem Bityutskiy (Битюцкий Артём)
  20 *          Adrian Hunter
  21 */
  22
  23/*
  24 * This file contains miscellaneous helper functions.
  25 */
  26
  27#ifndef __UBIFS_MISC_H__
  28#define __UBIFS_MISC_H__
  29
  30/**
  31 * ubifs_zn_dirty - check if znode is dirty.
  32 * @znode: znode to check
  33 *
  34 * This helper function returns %1 if @znode is dirty and %0 otherwise.
  35 */
  36static inline int ubifs_zn_dirty(const struct ubifs_znode *znode)
  37{
  38        return !!test_bit(DIRTY_ZNODE, &znode->flags);
  39}
  40
  41/**
  42 * ubifs_zn_obsolete - check if znode is obsolete.
  43 * @znode: znode to check
  44 *
  45 * This helper function returns %1 if @znode is obsolete and %0 otherwise.
  46 */
  47static inline int ubifs_zn_obsolete(const struct ubifs_znode *znode)
  48{
  49        return !!test_bit(OBSOLETE_ZNODE, &znode->flags);
  50}
  51
  52/**
  53 * ubifs_zn_cow - check if znode has to be copied on write.
  54 * @znode: znode to check
  55 *
  56 * This helper function returns %1 if @znode is has COW flag set and %0
  57 * otherwise.
  58 */
  59static inline int ubifs_zn_cow(const struct ubifs_znode *znode)
  60{
  61        return !!test_bit(COW_ZNODE, &znode->flags);
  62}
  63
  64/**
  65 * ubifs_wake_up_bgt - wake up background thread.
  66 * @c: UBIFS file-system description object
  67 */
  68static inline void ubifs_wake_up_bgt(struct ubifs_info *c)
  69{
  70        if (c->bgt && !c->need_bgt) {
  71                c->need_bgt = 1;
  72                wake_up_process(c->bgt);
  73        }
  74}
  75
  76/**
  77 * ubifs_tnc_find_child - find next child in znode.
  78 * @znode: znode to search at
  79 * @start: the zbranch index to start at
  80 *
  81 * This helper function looks for znode child starting at index @start. Returns
  82 * the child or %NULL if no children were found.
  83 */
  84static inline struct ubifs_znode *
  85ubifs_tnc_find_child(struct ubifs_znode *znode, int start)
  86{
  87        while (start < znode->child_cnt) {
  88                if (znode->zbranch[start].znode)
  89                        return znode->zbranch[start].znode;
  90                start += 1;
  91        }
  92
  93        return NULL;
  94}
  95
  96/**
  97 * ubifs_inode - get UBIFS inode information by VFS 'struct inode' object.
  98 * @inode: the VFS 'struct inode' pointer
  99 */
 100static inline struct ubifs_inode *ubifs_inode(const struct inode *inode)
 101{
 102        return container_of(inode, struct ubifs_inode, vfs_inode);
 103}
 104
 105/**
 106 * ubifs_compr_present - check if compressor was compiled in.
 107 * @compr_type: compressor type to check
 108 *
 109 * This function returns %1 of compressor of type @compr_type is present, and
 110 * %0 if not.
 111 */
 112static inline int ubifs_compr_present(int compr_type)
 113{
 114        ubifs_assert(compr_type >= 0 && compr_type < UBIFS_COMPR_TYPES_CNT);
 115        return !!ubifs_compressors[compr_type]->capi_name;
 116}
 117
 118/**
 119 * ubifs_compr_name - get compressor name string by its type.
 120 * @compr_type: compressor type
 121 *
 122 * This function returns compressor type string.
 123 */
 124static inline const char *ubifs_compr_name(int compr_type)
 125{
 126        ubifs_assert(compr_type >= 0 && compr_type < UBIFS_COMPR_TYPES_CNT);
 127        return ubifs_compressors[compr_type]->name;
 128}
 129
 130/**
 131 * ubifs_wbuf_sync - synchronize write-buffer.
 132 * @wbuf: write-buffer to synchronize
 133 *
 134 * This is the same as as 'ubifs_wbuf_sync_nolock()' but it does not assume
 135 * that the write-buffer is already locked.
 136 */
 137static inline int ubifs_wbuf_sync(struct ubifs_wbuf *wbuf)
 138{
 139        int err;
 140
 141        mutex_lock_nested(&wbuf->io_mutex, wbuf->jhead);
 142        err = ubifs_wbuf_sync_nolock(wbuf);
 143        mutex_unlock(&wbuf->io_mutex);
 144        return err;
 145}
 146
 147/**
 148 * ubifs_encode_dev - encode device node IDs.
 149 * @dev: UBIFS device node information
 150 * @rdev: device IDs to encode
 151 *
 152 * This is a helper function which encodes major/minor numbers of a device node
 153 * into UBIFS device node description. We use standard Linux "new" and "huge"
 154 * encodings.
 155 */
 156static inline int ubifs_encode_dev(union ubifs_dev_desc *dev, dev_t rdev)
 157{
 158        if (new_valid_dev(rdev)) {
 159                dev->new = cpu_to_le32(new_encode_dev(rdev));
 160                return sizeof(dev->new);
 161        } else {
 162                dev->huge = cpu_to_le64(huge_encode_dev(rdev));
 163                return sizeof(dev->huge);
 164        }
 165}
 166
 167/**
 168 * ubifs_add_dirt - add dirty space to LEB properties.
 169 * @c: the UBIFS file-system description object
 170 * @lnum: LEB to add dirty space for
 171 * @dirty: dirty space to add
 172 *
 173 * This is a helper function which increased amount of dirty LEB space. Returns
 174 * zero in case of success and a negative error code in case of failure.
 175 */
 176static inline int ubifs_add_dirt(struct ubifs_info *c, int lnum, int dirty)
 177{
 178        return ubifs_update_one_lp(c, lnum, LPROPS_NC, dirty, 0, 0);
 179}
 180
 181/**
 182 * ubifs_return_leb - return LEB to lprops.
 183 * @c: the UBIFS file-system description object
 184 * @lnum: LEB to return
 185 *
 186 * This helper function cleans the "taken" flag of a logical eraseblock in the
 187 * lprops. Returns zero in case of success and a negative error code in case of
 188 * failure.
 189 */
 190static inline int ubifs_return_leb(struct ubifs_info *c, int lnum)
 191{
 192        return ubifs_change_one_lp(c, lnum, LPROPS_NC, LPROPS_NC, 0,
 193                                   LPROPS_TAKEN, 0);
 194}
 195
 196/**
 197 * ubifs_idx_node_sz - return index node size.
 198 * @c: the UBIFS file-system description object
 199 * @child_cnt: number of children of this index node
 200 */
 201static inline int ubifs_idx_node_sz(const struct ubifs_info *c, int child_cnt)
 202{
 203        return UBIFS_IDX_NODE_SZ + (UBIFS_BRANCH_SZ + c->key_len) * child_cnt;
 204}
 205
 206/**
 207 * ubifs_idx_branch - return pointer to an index branch.
 208 * @c: the UBIFS file-system description object
 209 * @idx: index node
 210 * @bnum: branch number
 211 */
 212static inline
 213struct ubifs_branch *ubifs_idx_branch(const struct ubifs_info *c,
 214                                      const struct ubifs_idx_node *idx,
 215                                      int bnum)
 216{
 217        return (struct ubifs_branch *)((void *)idx->branches +
 218                                       (UBIFS_BRANCH_SZ + c->key_len) * bnum);
 219}
 220
 221/**
 222 * ubifs_idx_key - return pointer to an index key.
 223 * @c: the UBIFS file-system description object
 224 * @idx: index node
 225 */
 226static inline void *ubifs_idx_key(const struct ubifs_info *c,
 227                                  const struct ubifs_idx_node *idx)
 228{
 229        return (void *)((struct ubifs_branch *)idx->branches)->key;
 230}
 231
 232/**
 233 * ubifs_current_time - round current time to time granularity.
 234 * @inode: inode
 235 */
 236static inline struct timespec ubifs_current_time(struct inode *inode)
 237{
 238        return (inode->i_sb->s_time_gran < NSEC_PER_SEC) ?
 239                current_fs_time(inode->i_sb) : CURRENT_TIME_SEC;
 240}
 241
 242/**
 243 * ubifs_tnc_lookup - look up a file-system node.
 244 * @c: UBIFS file-system description object
 245 * @key: node key to lookup
 246 * @node: the node is returned here
 247 *
 248 * This function look up and reads node with key @key. The caller has to make
 249 * sure the @node buffer is large enough to fit the node. Returns zero in case
 250 * of success, %-ENOENT if the node was not found, and a negative error code in
 251 * case of failure.
 252 */
 253static inline int ubifs_tnc_lookup(struct ubifs_info *c,
 254                                   const union ubifs_key *key, void *node)
 255{
 256        return ubifs_tnc_locate(c, key, node, NULL, NULL);
 257}
 258
 259/**
 260 * ubifs_get_lprops - get reference to LEB properties.
 261 * @c: the UBIFS file-system description object
 262 *
 263 * This function locks lprops. Lprops have to be unlocked by
 264 * 'ubifs_release_lprops()'.
 265 */
 266static inline void ubifs_get_lprops(struct ubifs_info *c)
 267{
 268        mutex_lock(&c->lp_mutex);
 269}
 270
 271/**
 272 * ubifs_release_lprops - release lprops lock.
 273 * @c: the UBIFS file-system description object
 274 *
 275 * This function has to be called after each 'ubifs_get_lprops()' call to
 276 * unlock lprops.
 277 */
 278static inline void ubifs_release_lprops(struct ubifs_info *c)
 279{
 280        ubifs_assert(mutex_is_locked(&c->lp_mutex));
 281        ubifs_assert(c->lst.empty_lebs >= 0 &&
 282                     c->lst.empty_lebs <= c->main_lebs);
 283        mutex_unlock(&c->lp_mutex);
 284}
 285
 286/**
 287 * ubifs_next_log_lnum - switch to the next log LEB.
 288 * @c: UBIFS file-system description object
 289 * @lnum: current log LEB
 290 *
 291 * This helper function returns the log LEB number which goes next after LEB
 292 * 'lnum'.
 293 */
 294static inline int ubifs_next_log_lnum(const struct ubifs_info *c, int lnum)
 295{
 296        lnum += 1;
 297        if (lnum > c->log_last)
 298                lnum = UBIFS_LOG_LNUM;
 299
 300        return lnum;
 301}
 302
 303#endif /* __UBIFS_MISC_H__ */
 304
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